Glasgow ended their rollercoaster Heineken Cup campaign by earning a narrow and jittery home win against the Dragons at Firhill. While the Warriors' display was never likely to emulate their heroics in Toulouse the previous weekend, they produced a gritty and streetwise display to avoid the group wooden spoon.

They had the better of the opening exchanges, with Colin Gregor missing a long-range penalty after less than a minute. His luck changed almost immediately when he found the target from 35 metres in the wake of a high challenge on fly-half Ruaridh Jackson. Gregor jumped back into the limelight in the 10th minute to repeat the dose after the Dragons killed the ball at a ruck.

Dragons No.10 James Arlidge had two opportunities to break his side's duck, but on both occasions he sent his efforts wide. Glasgow then continued to have the bulk of possession and territory - only to find themselves adrift four minutes before the interval.

Arlidge and Tal Selley combined to take the ball into the danger zone, where a brilliant Max Evans tackle halted Ashley Smith. The visitors were awarded a penalty and their decision to run instead of going for three points paid off as hooker Tom Willis slid over in the corner.

Arlidge's conversion was from the widest possible angle, however he atoned for his earlier misses with an accurate strike. To add to the Warriors' worries, Gregor squandered his next pot at goal, while Palepoi and Justin Va'a both let the ball slip from their grasp to spoil promising raids.

It was a different picture after the restart as Glasgow snatched back the initiative with a superb try - started and finished by Jackson. He sparked panic stations among the Dragons back-ranks with a deft chip which was then hacked on by Thom Evans.

And following two scrums close to the line, Bernardo Stortoni entered the line to create the time and space for Jackson to streak over. Gregor added the extras from a wide angle to inject further confidence.

But instead of building on their lead, Glasgow grew careless again and were pinned back in their own half for long periods - although during this sequence the Welshmen did not look likely to burst through. However, a tense finale was ensured as Shaun Connor slotted a penalty 11 minutes from time to narrow the gap to three.

Glasgow boss Sean Lineen derided the visitors, criticising the negative aspects of their play and also the naïve performance of rookie referee Jerome Garces.

"This was a completely different experience to last week in Toulouse for us," he said. "When you are facing a team who don't want to play and a French referee, it can make it very difficult. We struggled to get any clean ball - but then they were lying all over it."

Lineen also fired a shot at his side however, criticising the drop in quality since last weekend's glorious display in France. "Some of our skill levels were amateurish and the decision-making was poor," he said. "But at the end of the day we got the win, which was brilliant. We just couldn't put them away."